Abstract: To enhance the seismic performance of existing hospital buildings located in high-intensity fortification areas and requiring higher fortification standards, efficient and reliable energy dissipation and seismic reduction reinforcement methods are explored for existing reinforced concrete frame structures upgraded from Class C to Class B fortification, in order to meet the seismic safety requirements under higher fortification standards. Taking an existing reinforced concrete frame inpatient building in Xi'an as a case study, the performance-based seismic design approach is adopted, incorporating buckling-restrained braces (BRBs) for energy dissipation and seismic mitigation. Through response spectrum analysis and dynamic elastoplastic time-history analysis, the study systematically compares the structural dynamic responses, energy dissipation, and member damage states under frequent and rare earthquakes before and after reinforcement. The results indicate that properly arranged BRBs significantly improve the structural torsional coupling effect; under frequent earthquakes, the maximum inter-story drift ratios in the x and y directions are reduced to 1/681 and 1/676, meeting the code limit of 1/550. Under rare earthquakes, the BRBs fully enter the plastic energy dissipation stage, reducing the maximum inter-story drift ratio from 1/51 (pre-reinforcement) to 1/145, with a decrease of approximately 72%. Beam-column damage is minimal, achieving the preset performance goals. The BRB reinforcement solution effectively enhances the seismic performance of critical public buildings in high-intensity seismic zones, achieving the preset performance targets and validating the effectiveness and feasibility of BRBs in such seismic reinforcement projects, providing practical reference for similar applications.